new light keeps blowing fuse, help...

[scarfficus]

Hi all wondered if there are any thoughts on this problem?

I have just tried to connect a new external light fitting, and it keeps blowing the fuse at the mains box.
The house is 1937 and has a "fuse wire" type mains box lighting curcuit on 5Amp. Which is due to be changed as part of a bigger project, but later.

I have taken a spur from the existing downstairs light curcuit, before it spurs to connect to the lighting roses in the lounge & hall. From this spur I have fed the new cable (1mm twin & earth) to the new light then onto the switch (in the same way as the lounge & hall) & also tried going to the switch then to the light.

The light works fine when the switch is in the on position but when i switch the switch to off the fuse blows? I have tried alternative switches and the same happens, so it is not the switch.

I have wired the light directly (without a switch) to the feed and this lights up fine?

I have checked the cables & it is not shorting anywhere, can anyone help with this?

Scarfficus

 

[Adam_151]

It is indeed shorting out... through the switch

Connect the switch in series with the lamp and it'll work fine

 

[DESL]

Turning switch to off position blows fuse.

So this causes a short to blow fuse which tells me that the switch is closing when off and is connecting L to N.

The only two things that could cause this is switch upside down or a 2 way switch with wires connected in comm and L2.

And somehow you have wired up the feed to the switch directly to L & N instead of as a switched pair.

 

[Steve]

He's just assuming that when the light is on, the switch is in its on position, regardless of which way up the rocker is.

 

[scarfficus]

Thanks for feedback,

The connection was made in L1 & COMM, NOT L2.

Can you please clarify the connection in series?
This is odd as it is comnnected as the lounge & hall lights & they work!

 

[Steve]

But what about in the light? Look at the diagrams in the wiki.

Your other lights work with this switch wiring because they are wired correctly in the light fitting.

 

[DESL]

Have you double checked the switch return is wired to live terminal of light fitting.

When you say spurred of from existing lighting cct how did you do this via junction box

 

[scarfficus]

Thanks for the advise guys, have looked into it futher on the "wiki" site, very usefull ! Have got Friday off so will re work it then, in day light! have capped it off safe till then with a junction box. will let you know how things get on. thanks again.

 

[DESL]

Where abouts in Essex are you?

 

[Steve]

Where abouts in Essex are you?

He's next door to you DESL

 

[DESL]

Where abouts in Essex are you?

He's next door to you DESL

I guess so if you're in T'North

 

[Steve]

Twas meant to be ironic - he's busy creating electrical faults, in the house next door to you = your house is at risk!

I'll get me coat

 

[DESL]

Didn't think you did irony in Yorkshire only parsimony

 

[kevnurse]

He's made 3 errors:

1. The wall switch is upside down. If it was the correct way up, he would definitely be breaking the contacts, so there is no way that a short could occur.

2. In the rose he has connected the lamp directly across the live feed and the neutral, so the lamp will always be on, except when he turns the light off at the switch, and shorts the circuit (lamp goes off) because he has also connected the switch acoss the live and and neutral.

 

[ricicle]

He's made 3 errors:

1. The wall switch is upside down. If it was the correct way up, he would definitely be breaking the contacts, so there is no way that a short could occur.

2. In the rose he has connected the lamp directly across the live feed and the neutral, so the lamp will always be on, except when he turns the light off at the switch, and shorts the circuit (lamp goes off) because he has also connected the switch acoss the live and and neutral.

There's 2, where's the other?